Hello everybody If R> a <- 1i+(1:10) I would like to say R> Im(a) <- 1:10 R> a [1] 1+ 1i 2+ 2i 3+ 3i 4+ 4i 5+ 5i 6+ 6i 7+ 7i 8+ 8i 9+ 9i 10+10i But there does not seem to be a "Im<-" function. How about this: "Im<-" <- function(x,value){ if(is.complex(value)){stop("value must be real")} if(all(value==0)){ return(Re(x)) } else { return(Re(x)+1i*value) } } comments anyone? can I infer that the above is a bad idea from the absence of a "Im<-"() function in R? -- Robin Hankin Uncertainty Analyst Southampton Oceanography Centre European Way, Southampton SO14 3ZH, UK tel 023-8059-7743